A UN envoy says the food situation in North Korea is desperate, with aid from the World Food Programme reaching only one-third of the those in need.

The UN rapporteur for North Korea said shortages had been in part caused by reactions to Pyongyang's nuclear tests, the BBC reported.

As a result, he said, only two million people are now getting food aid.

The envoy says food supplies have also been affected by the state's efforts to control economic activity, particularly by restricting the role of women.

Vitit Muntarbhorn, a Thai human-rights expert who has been UN Special Rapporteur for North Korea since 2004, was giving his final report to a meeting of UN members.

"The human rights situation in the country remains abysmal owing to the repressive nature of the power base: at once cloistered, controlled and callous," he said.